MAb Passive Vaccination against Acinetobacter baumannii

项目摘要/摘要 与其他耐药细菌不同的是，几乎没有抗生素正在研制中，以应对鲍曼不动杆菌。 迫切需要新的战略来预防和治疗这些感染。我们花了第一个资助期 将单抗提高到鲍曼不动杆菌胶囊，现已鉴定出4株抗包膜单抗(其中2株用于 产生一种双特异性单抗，留给我们3个单抗分子)，它们共同结合80%-90%的美国临床 隔离和保护小鼠免受致命感染。这3个领先候选人都是非常有潜力的，达到了100% 单剂量≤50微克对菌血症模型的保护作用。它们对肺炎模型也有保护作用 感染，并与抗菌药协同作用。此外，与双特异性单抗相比，双特异性单抗的效价更高。 对其每个单独的单抗，并保留对所有目标菌株的结合，并在体内有效。这一领先优势为3- MAB治疗已经开始转化为完整的GMP和毒性，并计划未来的I期临床试验。 我们更新的目标是增强临床开发和部署的可行性 通过缩小针对国际毒株的任何覆盖差距，定义替代效力标记，以及 验证支持临床试验和未来临床部署的关键分析。我们已经获得了一个新的全球 菌株收集，并为实现这些目标建立了关键伙伴关系，包括多价单抗方面的专家 综合、临床微生物学实验室操作、统计。我们的目标是： 具体目标1：确定和优化菌株覆盖率和替代药效标记 鲍曼不动杆菌临床分离株。我们收集了台湾，东南亚，中国， 欧洲和南美。我们将针对所有获得的菌株检测我们的3株单抗，评估流动结合。 和巨噬细胞摄取，并将评估在我们的IV菌血症模型中对代表菌株的疗效。我们 将根据需要筹集新闻单抗，以缩小国际压力报道差距。 具体目标2：验证生物测定，以便能够对单抗进行临床试验，包括效力和人体试验 代用功效标记物。我们将验证LC-MS/MS对我们的 不同于背景抗体的可变区，用于量化我们的单抗在注入人体血液时的数量。我们 将采用我们成熟的HL-60分析方法来定量人血浆中单抗的光学活性。最后，我们 将使用多重Luminex分析来量化新鲜人类白细胞的细胞因子调节。 具体目标3：优化快速体外结合试验作为“药敏试验”--相当于 支持单抗的临床试验和部署。我们将验证快速、高吞吐量的流绑定 检测与对小鼠的保护相关联，将其视为“敏感性测试等价物”。 针对鲍曼不动杆菌感染的新解决方案是一个关键的未得到满足的需求。我们已经研制出一种很有前途的单抗 在小鼠血液和肺部感染期间改善结果的方案。我们将定义全球菌株 覆盖范围，填补任何已确定的差距，并开发生物检测方法，以支持单抗的临床测试。

PROJECT SUMMARY/ABSTRACT In contrast to other resistant bacteria, virtually no antibiotics are in the pipeline to deal with XDR A. baumannii. There is a critical need for new strategies to prevent and treat these infections. We spent the first grant period raising MAbs to A. baumannii capsule, and have now identified 4 anti-capsular MAbs (2 of which were used to generate a bi-specific MAb, leaving us with 3 MAb molecules) that collectively bind to 80-90% of US clinical isolates and protect mice from lethal infection. These 3 lead candidates are all highly potent, achieving 100% protection in bacteremia models at single doses of ≤ 50 µg. They are also protective in pneumonia models of infection, and synergize with antibacterials. Furthermore, the bi-specific MAb has increased potency compared to each of its individual MAbs, and retains binding for all target strains, and efficacy in vivo. This lead three- MAb therapeutic has begun translation into full GMP and toxicity, planning for a future Phase I clinical trial. Our goals for the renewal are to enhance feasibility of clinical development and deployment of the MAbs by closing any coverage gaps against international strains, defining surrogate efficacy markers, and validating key assays to support clinical trials and future clinical deployment. We have obtained a new global strain collection, and entered into key partnerships to further these aims, including experts at multi-valent MAb synthesis, clinical microbiology laboratory operations, and statistics. Our Aims are to: Specific Aim 1: Define and optimize strain coverage and surrogate efficacy markers for international clinical strains of A. baumannii. We have collected 50 strains each from Taiwan, Southeast Asia, China, Europe, and South America. We will survey our 3 MAbs against all acquired strains, assessing flow binding and macrophage uptake, and will assess efficacy in our IV bacteremia model for representative strains. We will raise news MAbs as needed to close international strain coverage gaps. Specific Aim 2: Validate bioassays to enable clinical trials of the MAbs, including potency and human surrogate efficacy markers. We will validate LC-MS/MS for the specific amino acid sequences of our variable regions to quantify our MAbs when spiked into human blood, distinct from background antibodies. We will adapt our well-established HL-60 assays to quantify opsonic activity of MAb in human plasma. Finally, we will use multiplex Luminex assays to quantify cytokine modulation of fresh human leukocytes. Specific Aim 3: Optimize a rapid in vitro binding assay as a “susceptibility testing”-equivalent to support clinical trials and deployment of the MAbs. We will validate rapid, high throughput flow binding assays to correlate with protection in mice as a “susceptibility-test equivalent”. Novel solutions for A. baumannii infections are a critical unmet need. We have developed a promising MAb regimen that improves outcomes during blood and lung infection in mice. We will define global strain coverage, close any identified gaps, and develop bioassays to support clinical testing of the MAbs.